Mechanism for discontinuing power to an implement drive during machine reverse travel (no power in reverse) with automatic reengagement

ABSTRACT

An apparatus, systems and methods for automatically disengaging and re-engaging a cutting implement on a mowing machine by disconnecting and connecting, respectively, electrical power to an implement drive means. Power to the implement drive means is disconnected or connected according to gear positions of transmission control levers provided on the mowing machine. At designated gear positions, cut-out switches associated with the implement drive means are effective to interrupt power to the implement drive means. Repositioning the control levers to non-designated gear positions restores power to the implement drive means. The automatic disengagement/re-engagement of the cutting implement based on the gear position of transmission control levers may be used for two lever zero-turn-ride-on mowing machines or more traditional single lever ride-on mowing machines.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the priority filing benefit of International PCTapplication PCT/US2003/040723 filed Dec. 19, 2003, and published underPCT 21(2) in the English language; and U.S. Provisional PatentApplication Ser. No. 60/434,893 filed Dec. 19, 2002.

BACKGROUND OF THE INVENTION

1. Field of Invention

This invention relates to lawn/turf mowing machines, and moreparticularly to an implement governing mechanism and method for suchmachines.

2. Description of Related Art

Lawn/turf mowing machines are well-known. Such machines commonly have aseparably operable engine and cutting deck mounted on a chassis. A gearshift lever, positioned in either forward gear or a reverse gear by theoperator, controls the direction of travel of the mowing machine.

Industry has recognized the safety concerns posed by mowing machineshaving cutting blades engaged when the mowing machines travel in areverse direction. For example, U.S. Pat. No. 3,984,867 provides amechanical interlock preventing cutting in reverse. U.S. Pat. No.3,999,643 discloses a mower having a transmission lever that, in thereverse position, opens a switch to disengage an electric clutchoperatively associated with the cutting blade. Newly proposed 2003/2004ANSI Safety Standard requires a No Mow In Reverse (NMIR) feature onmowing machines. U.S. Pat. No. 6,026,634 also discloses disengagement ofthe cutting blades when a zero turn radius (ZTR) mowing machine is infull reverse gear.

Current technology for precluding the engagement of cutting blades forself-propelled and ride-on machines includes:

-   a. A mechanical means that blocks reverse drive of the mowing    machine when cutting blades are engaged.-   b. An electronic means that blocks reverse drive of the mowing    machine when cutting blades are engaged.-   c. An electronic means that automatically disconnects power to the    cutting blades when the mowing machine's directional control is    changed into Reverse. These systems are usually equipped with a    “latching relay” that requires the system to be reset to re-engage    the cutting blades in machine “Neutral” or “Forward” travel    directions.-   d. A mechanical means that disconnects power to the cutting blades    when the mowing machine's directional control is changed to Reverse    and requires the system to be reset to re-engage the cutting blades    when the machine direction control is returned to Neutral or Forward    travel directions.

In a and b above, shifting into reverse is prevented, whereas in c and dabove, use of the cutting blades is prevented until the system is reset.In order to satisfy the above safety concerns about cutting in reversewhile still allowing for optimal operator convenience, it is desirableto provide a lawn/turf mowing machine in which the cutting blades areautomatically disengaged in reverse and then automatically re-engagedsolely by shifting the mowing machine into an appropriate gear position.

SUMMARY OF THE INVENTION

Various exemplary embodiments of the apparatus, systems, and methodsaccording to the present invention provide for the automaticdisconnection or connection of power to an implement drive means, forexample an electrical blade clutch, of a mowing machine. Power to theimplement drive means can be automatically disconnected or connectedsolely by the respective positioning of the mowing machine'stransmission control levers. The present system does not require themachine operator to activate a separate reset switch in order todisconnect or reconnect power to the implement drive means. In all ofthe various embodiments of the invention, the engine of the mowingmachine continues to run regardless of the operational state of theimplement drive means.

In one aspect of the present invention, the mowing machine comprises apair of transmission control levers which selectively control theposition of a corresponding pair of parallel connected cut-out switches.The parallel connected cut-out switches in turn control the flow ofcurrent to the implement drive means. According to this particularembodiment, at least one of the parallel switches must be closed inorder to connect power to the implement drive means; that is, at leastone of the transmission control levers must be positioned in forward orneutral gear.

In other embodiments of the invention, for example, where a singletransmission control lever is provided on the mowing machine, a singlecutout switch is used to control the flow of current to the implementdrive means. In this alternative embodiment, the single cut-out switchmust be closed in order to connect power to the implement drive means;that is, the single transmission control lever must be shifted out ofreverse. However, in any of the exemplary embodiments of the presentinvention disclosed herein, the power to the implement drive means canbe controlled solely by the respective positioning of the transmissioncontrol lever(s).

Automatic disengagement and subsequent reengagement of the cuttingimplement means is suitable for a variety of mowing machines including,but not limited to, zero turn ride on (ZTR) machines having twotransmission control levers, or for more traditional ride-on mowingmachines having a single transmission control lever. Such automaticdisengagement and reengagement of the implement drive means based on thepositioning of the transmission control levers provides increasedoperator convenience and complies with the proposed safety standards.

These and other features and advantages of this invention are describedin, or are apparent from, the following detailed description of variousexemplary embodiments of the systems and methods according to thisinvention.

BRIEF DESCRIPTION OF THE DRAWINGS

Various exemplary embodiments of the systems and methods of thisinvention will be described in detail with reference to the followingfigures, wherein:

FIG. 1 illustrates an exemplary embodiment of a two-control lever ZTRmowing machine according to the invention;

FIG. 2 illustrates an exploded view of various transmission controllever components of the exemplary ZTR of FIG. 1;

FIG. 3 illustrates an exemplary disengagement/re-engagement deviceaccording to the invention;

FIG. 4 illustrates an exemplary circuit diagram of the ZTR system ofFIGS. 1-3;

FIG. 5 illustrates an exemplary ZTR transmission control lever in aneutral gear position; and

FIG. 6 illustrates an exemplary ZTR transmission control lever in areverse gear position.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

FIG. 1 shows an exemplary two-control lever ZTR mowing machine 1according to one embodiment of the invention. The ZTR mowing machine 1is comprised of a frame 10 supporting an operator seat 11, an engine 12to the rear of the operator seat, and a foot platform 13 to the front ofthe operator seat. Right and left drive wheels 14, 15 are provided tothe rear of the mowing machine 1. Right and left driven wheels 16, 17are provided to the front of the mowing machine. A grass cutting unit 18is provided under the foot platform 13. The grass cutting unit 18includes a cutting implement 20, such as cutting blades, attached to aspindle axle 22. An implement drive means 24 (FIG. 4), such as anelectric blade clutch, for example, drives the spindle axle 22 to engagethe blades 20. A controllable accessory power take off drive (PTO) iselectrically coupled to the electric blade clutch via a PTO switch 111.The PTO switch has “ON” and “OFF” positions. When the PTO switch is inan “ON” position, the PTO may be connected with the electric bladeclutch to engage the cutting blades, and when the PTO switch is in the“OFF” position, the PTO is not connected to the electric blade clutchand the cutting blades are not engaged. Cut-out switches 60 determinewhether the PTO is connected or disconnected with the electric bladeclutch when the PTO switch is in the “ON” position.

A transmission system 30 comprises right and left speed/directionalcontrol levers 32, 34 that are manually shiftable by an operator betweenforward, neutral and reverse gear positions. The control levers arepivotably mounted to the foot platform 13, or frame 10, on either sideof the operator's seat 11, for example. Each of the right and leftcontrol levers 32, 34 are associated with a corresponding right and leftdrive transaxle 70. Each transaxle 70 governs the speed and direction ofrotation of the corresponding right and left drive wheels 14, 15 basedon the gear position of each control lever 32, 34. The control levers32, 34 are independently operable whereby positioning both controllevers into a forward gear position towards a front F of the mowingmachine causes the mowing machine to travel in a generally straight andforward direction, whereas positioning both control levers into areverse gear position towards the rear R of the mowing machine causesthe mowing machine to travel in a generally straight and reversedirection. Positioning one of the control levers into a forward orreverse gear position and positioning of the other of the control leversinto one of a neutral or opposite gear position causes turning of themowing machine.

FIG. 2 shows, more specifically, various components associated with eachof the control levers 32, 34. A plate 31 connects each of the controllevers to the mowing machine. Each plate 31 is mounted to a bracket 37which is in turn connected to a pivot weldment 36. Each pivot weldment36 is connected to a pivot shaft 38. The pivot shafts 38 are then eachconnected to linkages 40, 41, 42. A universal coupling 43 coordinatesthe interface of the various linkages 40, 41, 42 with one another. Eachlinkage 42 also connects to a respective drive transaxle 70 to translatepower to an associated one of the right and left drive wheels 14, 15 ofthe mowing machine 1 via conventional means according to the selectedgear position. For example, the linkage 42 associated with the rightcontrol lever 32 is connected with the drive transaxle 70 that drivesthe right drive wheel 14, whereas the linkage 42 associated with theleft side control lever 34 is connected with the drive transaxle 70 thatdrives the left drive wheel 15. The connections between the variouscomponents described herein may be by combinations of nuts, bolts, andwashers as generally shown, or by other known or later developedconnection structures suitable to accommodate the necessary motions tothe linkages 40, 41, 42 or other components required in this system.

FIG. 3 shows an exemplary two-position, normally closed cut-out switch60 according to the invention. Each cut-out switch 60 includes a plunger61, a leaf spring 62, a mounting bracket 63, and an electrical coupler64. Depression of the plungers 61 by biasing contact of the controllevers with the leaf springs 62 renders the cut-out switches 60 open,whereas extension of the plungers by non-biasing contact of the leafsprings 62 with the control levers returns the cut-out switches 60 totheir normally closed state. The position of the control levers 32, 34thus controls the speed/direction of the mowing machine and the open orclosed state of the cut-out switches 60.

Referring to FIGS. 1-3, right and left cut-out switches 60 are mounted,via brackets 63, to right and left sides of the mowing machine. Eachcut-out switch is mounted within contacting range of a corresponding oneof the control levers 32, 34 such that sufficient contact by one of thecontrol levers biases a corresponding leaf spring to depress a plunger.The cut-out switches 60 are mounted such that the leaf springs 62 are inbiasing contact with the plungers 61 so that the plungers are depressedwhen a corresponding control lever is shifted into at least the reversegear position. When the plungers 61 are not in biasing contact with acontrol lever, the plungers extend. Depression of the plungerscorresponds to the open state of the cut-out switches, whereas extensionof the plungers corresponds to the closed state of the cut-out switches.

In a particularly preferred embodiment of the invention, referring stillto FIGS. 1-3, each cut-out switch 60 is mounted to the frame 10 of themowing machine below the operator's seat 11 and to the front of thecontrol levers 32, 34. At a bottom of each control lever, a pivotweldment 36 is provided with a roller 50. As the control levers areshifted into a reverse gear position, for example, the roller 50biasingly contacts, or attaches, to the leaf springs 62 of the cut-outswitches 60. When so contacted, each leaf spring 62 depresses theplungers 61 rendering the cut-out switches 60 open. As a result, theconnection between the electric blade clutch 24 and the PTO is brokenand power to the electronic blade clutch 24 is interrupted. When powerto the electric blade clutch 24 is interrupted, the cutting blades 20are automatically disengaged. Repositioning at least one of the controllevers 32, 34 into one of the neutral or forward gear positions, forexample, results in the respective plunger 61 extending, thereby closingthe cut-out switch 60 and completing the connection between the electricblade clutch and the PTO. Therefore, extending the plunger of at leastone cut-out switch effectively provides power to the electric bladeclutch 24 and automatically re-engages the cutting blades 20.

According to various other embodiments of the invention, as the artisanshould appreciate, the cut-out switches 60 may be mounted at a varietyof locations on the mowing machine and still be within biasing contactrange of the control levers such that the cutting blades areautomatically disengaged whenever the control levers are in the reversegear position. The exemplary embodiment shown in FIG. 1 shows thecut-out switches 60 mounted to the frame 10 in front of the controllevers 32, 34 on either side of the mowing machine. The artisan shouldreadily appreciate that the cut-out switches 60 could as well be mountedto the frame 10 to the rear of the control levers, or to the footplatform 13 to the front or rear of the control levers provided thecut-out switches are within biasing contact range of the levers 32, 34when the control levers are in a reverse gear position.

Referring now to FIG. 4, there is shown a detailed electric controlcircuit 100 for the mowing machine 1. The electric control circuitincludes a two-position PTO switch 111 having a ganged movable contactarrangement 111A-G, 111B-E, and 111C-F. Each ganged movable contactarrangement is simultaneously movable between the respective OFF and ONpositions. When the PTO switch 111 is in the OFF position (as shown),movable contact arrangement 111A-G is closed, while movable contactarrangements 111B-E and 111C-F are open. When the PTO switch is in theON position, movable contact arrangement 111A-G is open, while movablecontact arrangements 111B-E and 111C-F are closed.

Movable PTO contact terminal 111A is connected to solenoid 118 viamovable contact arrangement 103E-C of brake switch 103. Fixed PTOcontact terminal 111G is connected to normally closed terminals 105A,113A of transmission switches 105, 113 (shown in neutral) and starterterminal 112S of key switch 112. In operation, if the PTO switch 111 isOFF (as shown), a complete connection is made between starter terminal112S and solenoid 118, so long as certain conditions are satisfied.Those conditions are satisfied when brake switch terminal 103E-C isclosed, seat switch 106 is open (seat occupied), and transmissionswitches 105, 113 are in neutral (as shown). Under these conditions, ifthe operator turns key switch 112 to the START position, contact is madebetween battery terminal 112B, starter terminal 112S, and lightsterminal 112L. This permits current from battery 114 to energize thesolenoid 118 and activate the starter 119, thereby starting the engine.

Once the engine is started, key switch 112 automatically moves from theSTART to RUN position. When the key switch moves to the RUN position,connection is made between battery terminal 112B, regulator terminal112R, and lights terminal 112L. Accordingly, connection between battery14 and regulator terminal 112R permits the regulation of gas and fuel tothe engine and the engine will continue to run. If the operator leavesthe seat while the engine is running, seat switch 106 returns to itsnormally closed position, allowing current (via inter-harness connector122) to activate second relay 109 and third relay 110, thereby providinga ground path (via non-activated first relay 108) for magneto 115.Accordingly, the engine will stop running.

The electric control circuit 100 further includes parallel connected cutout switches 60. The cut-out switches are connected in series/parallel;that is, the cut-out switches are connected in parallel with each otherand connected in series between the electric blade clutch 24 and PTOcontact terminal 111F. When the PTO switch 111 is ON, movable contactterminals 111B and 111C are closed to engage their respective fixedcontacts 111E and 111F, while movable contact 111A is opened from itsrespective fixed contact 111G. In operation, assuming brake switch 103is OFF (as shown) and PTO switch 111 is ON, a complete circuit isprovided between the charging unit 116, battery 114 and electric bladeclutch 24 via closed PTO contact arrangement 111F-C, thereby energizingthe electric blade clutch 24 and engaging the cutting blades 20. If oneof the cut-out switches 60 is open, as by depression of its plunger 61,and the other parallel cut-off switch remains closed, a closed currentpath is still provided to the electric clutch blade 24 via the remainingclosed parallel circuit branch so that current continues to energizeelectric blade clutch 24, thereby allowing the cutting blades 20 toremain engaged. On the other hand, if both of the cut-out switches 60are open, as by depression of both of their plungers 61, the currentpath in both parallel branches between PTO terminal 111F and electricblade clutch 24 is interrupted, thereby de-activating the electric bladeclutch and disengaging the cutting blades. Accordingly, when in a “full”reverse position with both of the plungers depressed, the cutting bladeis not engaged by the electric switch. Once one of the plungers isextended (i.e., not depressed), the electric blade clutch is againactivated, connecting the drive system to the cutting blade(s).

FIG. 5 illustrates an example of one of the control levers in a neutralgear position whereby the leaf spring 62 associated with cut-out switch60 is not contacted, and the plunger 61 is not depressed. Conversely,FIG. 6 illustrates an example of a control lever in a reverse gearposition whereby the roller 50 is in biasing contact, or attaches, tothe leaf spring 62, thereby depressing the plunger 61 of the cut-outswitch 60.

In operation, assuming the transmission is in neutral, brake switch103E-C is closed, and the operator seat is occupied, the mowing machineis started by turning the key switch 112 to the START position. Once themowing machine is started, the key switch 112 automatically moves to theRUN position. Once the mowing machine is running, the cutting blades canbe engaged by turning the PTO switch to the “ON” position. When the PTOswitch is in the “ON” position, electrical connection between the PTOand the electric blade clutch is achieved so that the electric bladeclutch drives the cutting blades. The operator then positions each ofthe transmission control levers to a desired forward, neutral or reversegear position. The cutting blades remain engaged so long as at least oneof the transmission control levers is in a neutral or forward gearposition. When both of the transmission control levers are in thereverse gear position, i.e., in “full” reverse, the bottom portion ofeach control lever depresses the plunger of a corresponding one of thecut-out switches. As a result, the PTO is electrically disconnected fromthe electric blade clutch and the cutting blades are disengaged.Positioning either, or both, of the control levers to a non-reverse,i.e., neutral or forward, gear position causes a corresponding cut-outswitch plunger to extend. Accordingly, extension of one, or both,cut-out switch plungers electrically re-connects the PTO with theelectric blade clutch and automatically re-engages the cutting blades.

The systems and methods described herein thus incorporate a minimalnumber of components arranged to automatically disconnect and connectpower to the electric blade clutch that drives the cutting blades.Automatic disengagement and re-engagement of the cutting blades isachieved as a result. Further, positioning of each of the control leversby rotary motion, as opposed to linear motion, to directly activate orde-activate a plunger of the various cut-out switches permits thecut-out switches to be mounted at a variety of positions. Further, thedirect activation of the cut-out switches by the rotary motion of thetransmission control levers increases the range whereat automaticdisengagement and re-engagement of the cutting blades will occur, andminimizes variations that might otherwise occur due to mis-alignment ofparts.

While this invention has been described in conjunction with theexemplary embodiments outlined above, it is evident that manyalternatives, modifications and variations will be apparent to thoseskilled in the art. Accordingly, the exemplary embodiments of theinvention, as set forth above, are intended to be illustrative, notlimiting. Various changes may be made without departing from the spiritand scope of the invention.

1. A mowing machine comprising: a frame; an engine; a cutting bladesrotatably mounted to the frame via an electric blade clutch; acontrollable accessory power take off drive (PTO) electrically coupledwith the electric blade clutch; a PTO switch associated with the PTO andthe electric blade clutch, the PTO switch having “ON” and “OFF”positions such that the PTO may energize the electric blade clutch whenthe PTO is in the “ON” position and electrical connection between thePTO and electric blade clutch exists; a pair of cut-out switcheselectrically connected to the PTO and the electric blade clutch; atransmission system governing the speed and rotational direction ofcorresponding right and left drive wheels; a pair of transmissioncontrol levers operatively associated with the transmission system, eachof the control levers being selectably movable into one of a forward,neutral or reverse gear position corresponding to a desired speed anddirection of travel of the right or left drive wheels; each of thecut-out switches being mounted to the mowing machine for selectivecontact or non-contact by a corresponding one of the control leverswhereby the cut-out switches electrically connect the PTO with theelectric blade clutch and engage the cutting blades when either or bothof the cut-out switches are in a first position and the PTO switch is“ON” and disconnect the PTO from the electric blade clutch and disengagethe cutting blades when both of the cut-out switches are in a secondposition, and contact or non-contact positioning of the control leverswith the switches determines whether the cut-out switches are in thefirst position or the second position, whereby the cutting blades may beautomatically engaged by placing one of said cut-out switches in thefirst position after both of said switches have been in said secondposition.
 2. The mowing machine of claim 1, wherein each cut-out switchfurther comprises: a mounting bracket; an electrical coupler; a leafspring; and a plunger, wherein each electrical coupler connects one ofthe cut-out switches with the PTO and the blade clutch, and eachmounting bracket mounts one of the cut-out switches to the mowingmachine, each cut-out switch being mounted such that biasing contact ofeach of the leaf springs by a corresponding one of the control leversdepresses the plungers, thereby placing the cut-out switches into thesecond position, and non-biasing contact of each of the leaf springs bythe corresponding control levers extends the plungers, thereby returningthe cut-out switches to the first position.
 3. The mowing machine ofclaim 2, wherein depression of the plunger occurs when a correspondingone of the control levers is placed into the reverse gear position. 4.The mowing machine of claim 2, wherein extension of the plunger occurswhen a corresponding one of the control levers is placed into one of theneutral or forward gear positions.
 5. The mowing machine of claim 2,wherein depression of the plunger occurs when a corresponding one of thecontrol levers is placed into either of the neutral or reverse gearpositions.
 6. The mowing machine of claim 5, wherein positioning ofeither of the control levers in the forward gear position causes acorresponding cut-out switch plunger to extend, thereby placing thecorresponding cut-out switch in its first position, re-connecting thePTO and the electric blade clutch, and re-engaging the cutting blades.7. The mowing machine of claim 2, wherein each cut-out switch isarranged in parallel relative to one another and in series between theelectric blade clutch and the PTO.
 8. The mowing machine of claim 2,wherein a bottom portion of each control lever contacts a correspondingone of the leaf springs.
 9. The mowing machine of claim 8, the bottomportion of each control lever further comprises: a plate; a sleevedbracket; a pivot weldment; a pivot shaft; a set of linkages, wherein oneside of each plate is mounted to the mowing machine and another side ofeach plate is mounted to the sleeved bracket, each pivot weldment isreceived in one of the sleeved brackets and is connected to one of thepivot shafts, each pivot shaft is connected to the one set of linkages,each set of linkages being associated with a corresponding right drivetransaxle or left drive transaxle, whereby the one set of linkagesdetermines the speed and rotational direction of a right drive wheel andthe other set of linkages determines the speed and rotational directionof a left drive wheel according to the gear positions of each controllever.
 10. A method of automatically disengaging and re-engaging cuttingblades of a mowing machine, the method comprising: providing the mowingmachine having an engine, a transmission, a pair of transmission controllevers, a controllable accessory power take off drive (PTO) coupled toan electric blade clutch, a PTO switch having an “ON” and “OFF”position, the cutting blades engagable by the electric blade clutch, anda pair of cut-out switch between the electric blade clutch and the PTO,each cut-out switch having a first position that connects the PTO withthe electric blade clutch when the PTO switch is “ON” and at least onecut-out switch is in the first position, and a second position thatdisconnects the PTO from the electric blade clutch when all cut-outswitches are in the second position; starting the engine; turning thePTO switch to an “ON” position; shifting at least one of thetransmission control levers into a non reverse gear position to place atleast one cut-out switch into the first position thereby connecting thePTO with the electric blade clutch and engaging the cutting blades;shifting all of the transmission control levers into the reverse gearposition to place all of the cut-out switches into the second positionthereby disconnecting the PTO switch from the electric blade clutch anddisengaging the cutting blades; and shifting at least one of thetransmission control levers into one of the non-reverse gear positionsto place at least one of the cut-out switches into the first positionthereby re-connecting the PTO with the electric blade clutch andre-engaging the cutting blades.
 11. The method of claim 10, wherein themowing machine is a the pair of transmission levers ZTR mowing machineand the cut-out switches are in parallel relative to one another and inseries between the PTO switch and the electric blade clutch.